RESUMO
Objective To detect the methylation status of the promoter of BNIP3 gene in gastric cancer cell lines MKN1,and to explore the mecha?nism of DNA methylation regulating the expression of BNIP3 in gastric cancer cells. Methods The methylation status of BNIP3 promoter was de?tected by bisulfate sequencing PCR. Reverse transcription PCR was used to evaluate BNIP3 mRNA expression. MKN1 cells were treated with 5?Aza?2′?deoxycytidine(5?Aza?CdR),and after the treatment,the methylation status and BNIP3 mRNA expression were observed. Chromatin immuno?precipitation(ChIP)was used to determine the combination of BNIP3 with DNA methyltransferase 1(DNMT1). Results The promoter DNA of BNIP3 in MKN1 cells was in state of hypermethylation. Compared to the control group,methylation status and mRNA expression of BNIP3 in the drug treatment group(the 5?Aza?CdR concentration was 10μmol/L)were reversed,which showed statistical differences(P<0.05). 5?Aza?CdR inhibited the combination of BNIP3 with DNMT1. Conclusion CpG island methylation regulates BNIP3 gene expression in MKN1 cells. DNA methylation is related with the binding between the promoter of BNIP3 and DNMT1.